The purpose of the project is to develop chemical methods for the systematic, unit-by-unit synthesis of oligosaccharides, for use as such and for incorporation into larger molecules. Work completed in this laboratory during the past year has shown that the scheme of attaching the first sugar to the support by a thioglycoside linkage is good approach to the synthesis of oligosaccharides by solid phase methods. In this work a benzylated 6-acetylated glucosyl bromide was used as the glycosyl donor for making alpha, 1 yields 6 linked oligosaccharides of D-glucose. Repeated treatments were necessary to obtain satisfactory yields in the coupling steps. It is therefore planned to test the more active benzylated 6-phenylcarbamoylated glucose 1-tosylate recently described by C. Schuerch as a donor of alpha, 1 yields 6 and alpha, 1 yields 4-linked D-glucose residues. Porous glass will be used as the solid support. The synthesis of tri-O-benzyl-l-thio-D-galactopyranoses is in progress. These are required as intermediates for the preparation, via the thioglycoside scheme, of oligosaccharides containing D-galactose as the reducing residue. This work will be directed toward products having beta-linked D-glucosamine and D-galactose as the additional sugars.